The present invention relates generally to the art of computer generated images and more particularly to a head-mounted display apparatus.
A virtual environmental display apparatus presents the viewer with an image, usually three dimensional, which changes as he/she moves. Computer generated images of an external scene (such as a view from the cockpit of a plane for flight simulation purposes) are presented on an LCD, cathode-ray tube, or similar display device. A position sensor attached to the viewer's head tracks the movement of the head and produces signals that are incorporated in the computation means which generate the image, to alter the image consistently with the alterations that would occur if the scene being simulated were being viewed directly. Thus, the viewer has the optical illusion of actually being in a computer generated "virtual" environment.
Typically, the display system, position sensor and other software are coupled to a head-mount that is placed on the viewer's head and connected to the computer that generates the image. One problem with present systems is that the poor ergonomics of the head-mounted display detract from the realism of the image. In some prior systems, the apparatus is very heavy and the weight is not balanced appropriately. The display system often outweighs the other components and, therefore, causes the head-mount to be too heavy in front. Thus, the viewer will grow uncomfortable after wearing the device for any length of time and, in some instances, the head-mount tends to tip forward. Another problem with the prior helmets is that such typical helmets are often extremely difficult to adjust, often requiring the user to take the helmet off his/her head and adjust it to the correct size. In addition, an important aspect of creating a virtual environment is providing a head-mount that will change shape to conform to various forehead sizes while maintaining a constant distance between the display and the viewer's eyes.
For these reasons, a head-mounted display apparatus is desired which is light weight and carefully balanced so that the viewer is comfortable while wearing the helmet for a long time. It is further desired that the helmet can be adjusted by an external mechanism so that the viewer can put the helmet on and adjust the size of the helmet easily. Preferably, the helmet will conform to various head shapes without changing the distance between the display and the viewer's eyes so that an optimal viewing position will be achieved for all viewers.